TITLE: GCN CIRCULAR NUMBER: 34565 SUBJECT: GRB 230826A: Swift detection of a burst DATE: 23/08/26 20:16:03 GMT FROM: David Palmer at LANL R. A. J. Eyles-Ferris (U Leicester), S. Dichiara (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 19:32:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230826A (trigger=1187463). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 83.012, +66.125 which is RA(J2000) = 05h 32m 03s Dec(J2000) = +66d 07' 30" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Preliminary quicklook data suggests that the light curve is doubly peaked with a T90 of ~50 sec and background subtracted peak count rate of ~4000 counts/sec at T0+3 sec. The XRT began observing the field at 19:34:03.7 UT, 76.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 83.05920, 66.12506 which is equivalent to: RA(J2000) = 5h 32d 14.2s, Dec(J2000) = 66h 07d 30.2s with an uncertainty of 10.0 arcseconds (radius, 90% containment). This location is 69 arcseconds from the BAT onboard position, within the BAT error circle. Due to a telemetry gap, no further information is available at this time. However a simultaneous Fermi trigger (GCN #34564) confirms the GRB. Burst Advocate for this burst is R. A. J. Eyles-Ferris (raje1 AT leicester.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)